Let \(S=S^0={_1,_2,\ldots , _n}, _i \in \)  be the initial dataset. We observe \(k\)  edit requests, each being either an insertion or deletion request. We use \(S^i\)  to denote the set of data points available at time \(i\)  in the stream. For notational simplicity, as in [1]}, we assume that at any point in the stream, the number of available data points is at least \(n/2\)  and at most \(2n\) .
